Wikipedia talk:Articles for deletion/Mechanical quantity

This article is very useful for teachers and students and I understand why it was flagged for deletion as no reliable reference can be found; but it is all standard physics, presented in a table where the quantities appear in the mass, time, length units to play around easily with the quantities. I have personally used it in my University lectures (as one the authors of the lecture video) and dimensional analysis was clearly easier with this support. I hope the previous comment by my colleague helped clarifying why we believe the page could stay, let us know if we need to amend it.

Mechanical Quantities

Hello all,

a couple of years ago I proposed a page dedicated to "Mechanical quantities", centered on a table based on their dimensions (of the form ML^xT^y). Although the quantities themselves (mass, force, energy, viscosity etc) are all standard, the way to arrange them into a table was "original" and so the article was taken down because it contained original research without reliable source. With my collaborators we since took some time to organize these ideas, which were recently published https://doi.org/10.1039/D4SM00263F or https://arxiv.org/abs/2401.15101 for free access. Given this new development I'd like to know if the persons who contributed to the deletion discussion in 2022 would consider that restoring the page would be legitimate. @SpinningSpark, @RL0919, @ΨΦΘ, @Quondum, @NebY, @Srleffler, @ComplexRational, @Doczilla

Thanks for your help Iluvendan (talk) 11:16, 19 June 2024 (UTC)

[I can't find a record of that discussion. My bad: here] The more I look at this, the more I think that it is a really bad idea to define a term "mechanical quantity" as a conveniently definable narrow category of quantities with specific properties when viewed from dimensional analysis by creating a stand-alone article on this. The term and related concepts have been around for much more than a century, but, like most broad terms for categories, have remained without a precise accepted definition. There are also many quantities that many would call "mechanical quantities" (rotational frequency, acceleration, mechanical advantage, etc.) that would be excluded. Simply having one paper using a term in a particular way does not establish notability of the use of that term in a broad, established context. I notice that the publication is in "Soft matter", a journal published by the Royal Society Chemistry. That journal can hardly speak to terminology across all disciplines involving physical quantities, which the suggested article would claim. The article is a long meandering essay/tutorial, and should not be taken to be saying anything new. Finally, the paper uses nonstandard notation for dimensions (calligraphic L, T, M), which flies in the face of existing standardization. This tells me that the authors are simply unaware of what is established in the field of metrology, and cannot be trusted to speak representatively. —Quondum 15:01, 19 June 2024 (UTC)

wow! Iluvendan (talk) 19:05, 19 June 2024 (UTC)

Please look at Wikipedia and ask yourself whether it's a repository of articles on every new piece of research or proposal, and whether academics spend their time producing Wikipedia articles on their own work. To understand why that is not the case, read our policies and guidelines on notability, original research, neutral point of view, conflicts of interest and what Wikipedia is not, among others. Don't read them looking for loopholes; they're not legal documents. Read them instead to understand in how many ways it is antithetical to the very ethos of Wikipedia for you to press for Wikipedia to have an article putting forward your ideas and for you to do so on the basis that a journal has published an article by you about them. NebY (talk) 08:56, 20 June 2024 (UTC)

I am very sorry if you felt pressed in anyway. I am simply asking for your opinions. There is an existing page that lists "physical quantities" (https://en.wikipedia.org/wiki/List_of_physical_quantities), the "mechanical" ones being a subset. The table we put forth suggests a way to arrange these mechanical quantities in a 2D array rather than a 1D list, to more easily see how their dimensions are connected. I also feel that this table could provide a nice tool to navigate to the various wiki pages associated with these quantities. Maybe a new page is not a good idea, but contributing to an existing page might. In any case, I'm not trying to impose any world view here, I just want to contribute to Wikipedia if I can. Thank you for pointing out those policies, I had already familiarized myself with them the first time around. Most of these concerns had been raised two years ago (WP:N, WP:V, WP:OR, WP:RS), but from my understanding the page was deleted as original research with no reliable sources cited. I completely agreed with that decision then. But now that these OR and RS issues have been somewhat alleviated I am curious to hear what people (including you two) think. Iluvendan (talk) 14:01, 20 June 2024 (UTC)

I come from a more neutral perspective than NebY (without disagreeing). Concepts such as geometric, kinematic and physical quantities seem to have fairly defined characteristics, and have been referred to extensively. Labelling the subset of physical quantities defined as of dimension ML^xT^y seems neither useful nor does it appear to have been found interesting in any disciple, hence my resistance to doing so. Is there a subset that is of interest that we should be looking at? One could argue that "mechanical quantities" refers to a useful subset, but it isn't this one, and what is excluded is completely unclear to me. —Quondum 17:04, 20 June 2024 (UTC)

Based on SI, there are 6 or 7 fundamental dimensions (depending on whether moles are considered dimensionless). These are recalled in the introduction of List_of_physical_quantities: length (L), time (T), mass (M), temperature (Θ), electric current (I), and luminous intensity (J). In theory a "physical quantity" could have dimensions combining these fundamental ones in any possible way. So for instance there could theoretically exist a physical quantity with dimensions L¹² T^π M^√2 Θ² I^-23044 J^-1/233. To my knowledge, such quantity has not yet found any practical use, and for very good reasons: the physical quantities that are useful are not random combinations of the possible dimensions. There are tacit rules that greatly reduce the choices, but I think these rules are not found in the wikipedia pages on these topics.

(I leave aside thermodynamics (using Θ), electromagnetism (I) and photometry (J), although what can be said in mechanics usually carries over to these disciplines.)

With Fourier, Maxwell etc I think it is fair to say that mechanics focuses on the dimensions M, L and T. Then a "mechanical quantity" in the most general sense could be any quantity with dimensions M^zL^xT^y. One might want to exclude the case x=y=z=0, which would just be a number, which can be found in disciplines beyond mechanics. Then, with the same logic one might also want to exclude geometric quantities with y=z=0 (lengths, areas, volumes, etc), or temporal quantities (x=z=0). Basically, there are remarkable subsets of "mechanical quantities" in the general sense, and some choice has to be made as to which one deserve its own label. For instance, the kinematic quantities (z=0) are of particular interest. But within the kinematic quantities only a few have been named (most notoriously: speed, acceleration, diffusivity). One tacit rule is that if a quantity with certain dimensions has been named, powers of these quantities may not need a name of their own. For instance LT^-1 is a speed/velocity, and so quantities with dimensions L^-1T, L²T^-2, (LT^-1)^a do not really need special recognition. There are of course exceptions, like Sorptivity. Under the same logic, a quantity M^zL^xT^y, might not need special recognition if the quantity M L^x/zT^y/z has already been named. And indeed, most quantities of the form M^zL^xT^y (z≠0) have z=1, for instance, 47 out of the 55 in the List_of_physical_quantities, the remaining 8 having z=-1. I think it is pretty clear that this kind of "mechanical quantity" (or whatever you want to call them) deserve some recognition. @Quondum When you say "Labelling the subset of physical quantities defined as of dimension ML^xT^y seems neither useful nor does it appear to have been found interesting in any disciple". I beg to differ. Iluvendan (talk) 08:14, 21 June 2024 (UTC)